A conventional electrical room dehumidifier operates on a same refrigeration principle, in that, moisture-laden air is generally drawn into the rear of the dehumidifier and over the cold evaporator coils by the fan. The moisture is condensed and deposited on the coils of the dehumidifier when the air is cooled and the water thus condensed will fall into a water container or is drained outwardly. However, such a conventional room dehumidifier may have the following drawbacks:
1. Ambient air will condense on a refrigerant evaporator of the room dehumidifier, in which a system is required to evaporate the refrigerant and to condense the refrigerant, causing a big space, heavy weight and noise pollution for the installation and operation of such a conventional dehumidifier. PA1 2. Cost will be higher to purchase, operate and maintain the conventional dehumidifier. PA1 3. For dehumidifying an interior of a tiny space such as in a cabinet, bookcase, wardrobe, or instrument room, a conventional larger dehumidifier will not be applicable.